Professor Megan Lancaster | How Genetics Could Predict Dangerous Heart Rhythms Early

While she was at Vanderbilt University Medical Center, one strand of Lancaster’s work looked at why certain medications can prolong the heart’s electrical reset in a small number of people while leaving most others unaffected.

In this study, nearly a thousand healthy volunteers were given a heart-rhythm-affecting drug and the research team compared the results with each person’s polygenic risk score – a measure that adds up the small effects of hundreds of thousands of genetic variations. People with higher scores were far more likely to experience a significant reaction.

In practice, this means doctors could one day check a patient’s genetic profile before prescribing certain drugs, focusing careful monitoring on those who actually need it.

Lancaster has also tackled a different piece of the puzzle: rare genetic mutations that cause inherited forms of Long QT syndrome but often go undetected because carriers never show obvious symptoms severe enough to prompt testing.

Working with large biobanks, which link DNA data to detailed health records for tens of thousands of people, she and her colleagues traced distant family relationships hidden in the genetic data, uncovering connections that would be invisible to a standard family history. People who share a rare mutation from a common ancestor also share surrounding stretches of DNA, even generations later.

Starting from a small group of diagnosed patients, the researchers searched these vast databases and uncovered dozens of previously unrecognised carriers, some with subtle signs of the condition that had simply never been picked up.

Together, these two strands of research show how genetic background shapes risk in different ways, and how they can combine, since someone with both a rare mutation and a high polygenic score is more likely to be strongly affected. For families living with the uncertainty of Long QT syndrome, this offers something rare: the chance to know, and to act, before a crisis occurs. As Lancaster’s work continues, a simple genetic test could become a routine part of protecting the heart’s steady, unassuming rhythm.